If $f(x)=int_{3}^x sqrt{1+t^3} dt$ Find $(f^{-1})'(0)$












2












$begingroup$


Consider the integral $$f(x)=int_{3}^x sqrt{1+t^3} dt$$



Using Theorem 7 from my textbook which is $$frac{1}{f'(f^{-1}(a))}$$



$f'(t)= frac{2t^3}{2sqrt{1+t^3}}$



$f^{-1}(t)=sqrt[3]{t^2-1}$



I get confused here because does the integral affect how I should proceed or should I have incorporated the integral from the start?










share|cite|improve this question











$endgroup$












  • $begingroup$
    Your derivative step is very wrong; a big red flag is the fact that you have a function of $x$ equal to a function of $t$.
    $endgroup$
    – T. Bongers
    Dec 10 '18 at 23:49










  • $begingroup$
    It was a force of habit, i'm used to $f(x)$
    $endgroup$
    – Eric Brown
    Dec 10 '18 at 23:51










  • $begingroup$
    It's still quite wrong. You've differentiated $sqrt{1 + t^3}$, not $f$. You've also just changed where the notation is incorrect to the previous line!
    $endgroup$
    – T. Bongers
    Dec 10 '18 at 23:52










  • $begingroup$
    Yeah so people like you don't comment on my tiny mistakes. I'm sleep deprived and over stressed, give me a break.
    $endgroup$
    – Eric Brown
    Dec 10 '18 at 23:55








  • 1




    $begingroup$
    The very first expression after “Consider the integral” is wrong: $f(t)$ should be $f(x)$. Also (here and in real life) I highly recommend that you don’t be rude to someone who’s trying to help you.
    $endgroup$
    – Shalop
    Dec 11 '18 at 0:13


















2












$begingroup$


Consider the integral $$f(x)=int_{3}^x sqrt{1+t^3} dt$$



Using Theorem 7 from my textbook which is $$frac{1}{f'(f^{-1}(a))}$$



$f'(t)= frac{2t^3}{2sqrt{1+t^3}}$



$f^{-1}(t)=sqrt[3]{t^2-1}$



I get confused here because does the integral affect how I should proceed or should I have incorporated the integral from the start?










share|cite|improve this question











$endgroup$












  • $begingroup$
    Your derivative step is very wrong; a big red flag is the fact that you have a function of $x$ equal to a function of $t$.
    $endgroup$
    – T. Bongers
    Dec 10 '18 at 23:49










  • $begingroup$
    It was a force of habit, i'm used to $f(x)$
    $endgroup$
    – Eric Brown
    Dec 10 '18 at 23:51










  • $begingroup$
    It's still quite wrong. You've differentiated $sqrt{1 + t^3}$, not $f$. You've also just changed where the notation is incorrect to the previous line!
    $endgroup$
    – T. Bongers
    Dec 10 '18 at 23:52










  • $begingroup$
    Yeah so people like you don't comment on my tiny mistakes. I'm sleep deprived and over stressed, give me a break.
    $endgroup$
    – Eric Brown
    Dec 10 '18 at 23:55








  • 1




    $begingroup$
    The very first expression after “Consider the integral” is wrong: $f(t)$ should be $f(x)$. Also (here and in real life) I highly recommend that you don’t be rude to someone who’s trying to help you.
    $endgroup$
    – Shalop
    Dec 11 '18 at 0:13
















2












2








2





$begingroup$


Consider the integral $$f(x)=int_{3}^x sqrt{1+t^3} dt$$



Using Theorem 7 from my textbook which is $$frac{1}{f'(f^{-1}(a))}$$



$f'(t)= frac{2t^3}{2sqrt{1+t^3}}$



$f^{-1}(t)=sqrt[3]{t^2-1}$



I get confused here because does the integral affect how I should proceed or should I have incorporated the integral from the start?










share|cite|improve this question











$endgroup$




Consider the integral $$f(x)=int_{3}^x sqrt{1+t^3} dt$$



Using Theorem 7 from my textbook which is $$frac{1}{f'(f^{-1}(a))}$$



$f'(t)= frac{2t^3}{2sqrt{1+t^3}}$



$f^{-1}(t)=sqrt[3]{t^2-1}$



I get confused here because does the integral affect how I should proceed or should I have incorporated the integral from the start?







calculus inverse-function






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Dec 11 '18 at 0:15







Eric Brown

















asked Dec 10 '18 at 23:39









Eric BrownEric Brown

737




737












  • $begingroup$
    Your derivative step is very wrong; a big red flag is the fact that you have a function of $x$ equal to a function of $t$.
    $endgroup$
    – T. Bongers
    Dec 10 '18 at 23:49










  • $begingroup$
    It was a force of habit, i'm used to $f(x)$
    $endgroup$
    – Eric Brown
    Dec 10 '18 at 23:51










  • $begingroup$
    It's still quite wrong. You've differentiated $sqrt{1 + t^3}$, not $f$. You've also just changed where the notation is incorrect to the previous line!
    $endgroup$
    – T. Bongers
    Dec 10 '18 at 23:52










  • $begingroup$
    Yeah so people like you don't comment on my tiny mistakes. I'm sleep deprived and over stressed, give me a break.
    $endgroup$
    – Eric Brown
    Dec 10 '18 at 23:55








  • 1




    $begingroup$
    The very first expression after “Consider the integral” is wrong: $f(t)$ should be $f(x)$. Also (here and in real life) I highly recommend that you don’t be rude to someone who’s trying to help you.
    $endgroup$
    – Shalop
    Dec 11 '18 at 0:13




















  • $begingroup$
    Your derivative step is very wrong; a big red flag is the fact that you have a function of $x$ equal to a function of $t$.
    $endgroup$
    – T. Bongers
    Dec 10 '18 at 23:49










  • $begingroup$
    It was a force of habit, i'm used to $f(x)$
    $endgroup$
    – Eric Brown
    Dec 10 '18 at 23:51










  • $begingroup$
    It's still quite wrong. You've differentiated $sqrt{1 + t^3}$, not $f$. You've also just changed where the notation is incorrect to the previous line!
    $endgroup$
    – T. Bongers
    Dec 10 '18 at 23:52










  • $begingroup$
    Yeah so people like you don't comment on my tiny mistakes. I'm sleep deprived and over stressed, give me a break.
    $endgroup$
    – Eric Brown
    Dec 10 '18 at 23:55








  • 1




    $begingroup$
    The very first expression after “Consider the integral” is wrong: $f(t)$ should be $f(x)$. Also (here and in real life) I highly recommend that you don’t be rude to someone who’s trying to help you.
    $endgroup$
    – Shalop
    Dec 11 '18 at 0:13


















$begingroup$
Your derivative step is very wrong; a big red flag is the fact that you have a function of $x$ equal to a function of $t$.
$endgroup$
– T. Bongers
Dec 10 '18 at 23:49




$begingroup$
Your derivative step is very wrong; a big red flag is the fact that you have a function of $x$ equal to a function of $t$.
$endgroup$
– T. Bongers
Dec 10 '18 at 23:49












$begingroup$
It was a force of habit, i'm used to $f(x)$
$endgroup$
– Eric Brown
Dec 10 '18 at 23:51




$begingroup$
It was a force of habit, i'm used to $f(x)$
$endgroup$
– Eric Brown
Dec 10 '18 at 23:51












$begingroup$
It's still quite wrong. You've differentiated $sqrt{1 + t^3}$, not $f$. You've also just changed where the notation is incorrect to the previous line!
$endgroup$
– T. Bongers
Dec 10 '18 at 23:52




$begingroup$
It's still quite wrong. You've differentiated $sqrt{1 + t^3}$, not $f$. You've also just changed where the notation is incorrect to the previous line!
$endgroup$
– T. Bongers
Dec 10 '18 at 23:52












$begingroup$
Yeah so people like you don't comment on my tiny mistakes. I'm sleep deprived and over stressed, give me a break.
$endgroup$
– Eric Brown
Dec 10 '18 at 23:55






$begingroup$
Yeah so people like you don't comment on my tiny mistakes. I'm sleep deprived and over stressed, give me a break.
$endgroup$
– Eric Brown
Dec 10 '18 at 23:55






1




1




$begingroup$
The very first expression after “Consider the integral” is wrong: $f(t)$ should be $f(x)$. Also (here and in real life) I highly recommend that you don’t be rude to someone who’s trying to help you.
$endgroup$
– Shalop
Dec 11 '18 at 0:13






$begingroup$
The very first expression after “Consider the integral” is wrong: $f(t)$ should be $f(x)$. Also (here and in real life) I highly recommend that you don’t be rude to someone who’s trying to help you.
$endgroup$
– Shalop
Dec 11 '18 at 0:13












1 Answer
1






active

oldest

votes


















4












$begingroup$

HINTS:



From the Fundamental Theorem of Calculus, we have



$$f'(x)=sqrt{1+x^3}$$



Moreover, note that



$$f(3)=0implies f^{-1}(0)=3$$



Finally, the theorem from your text book reveals that



$$frac{df^{-1}(x)}{dx}=frac1{sqrt{1+(f^{-1}(x))^3}}$$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Is my inverse function correct though?
    $endgroup$
    – Eric Brown
    Dec 11 '18 at 0:04










  • $begingroup$
    Hi Eric. No, the inverse of $int_3^xsqrt{1+t^3},dt$ is not $sqrt[3]{x^2-1}$ .
    $endgroup$
    – Mark Viola
    Dec 11 '18 at 0:11











Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3034655%2fif-fx-int-3x-sqrt1t3-dt-find-f-10%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









4












$begingroup$

HINTS:



From the Fundamental Theorem of Calculus, we have



$$f'(x)=sqrt{1+x^3}$$



Moreover, note that



$$f(3)=0implies f^{-1}(0)=3$$



Finally, the theorem from your text book reveals that



$$frac{df^{-1}(x)}{dx}=frac1{sqrt{1+(f^{-1}(x))^3}}$$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Is my inverse function correct though?
    $endgroup$
    – Eric Brown
    Dec 11 '18 at 0:04










  • $begingroup$
    Hi Eric. No, the inverse of $int_3^xsqrt{1+t^3},dt$ is not $sqrt[3]{x^2-1}$ .
    $endgroup$
    – Mark Viola
    Dec 11 '18 at 0:11
















4












$begingroup$

HINTS:



From the Fundamental Theorem of Calculus, we have



$$f'(x)=sqrt{1+x^3}$$



Moreover, note that



$$f(3)=0implies f^{-1}(0)=3$$



Finally, the theorem from your text book reveals that



$$frac{df^{-1}(x)}{dx}=frac1{sqrt{1+(f^{-1}(x))^3}}$$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Is my inverse function correct though?
    $endgroup$
    – Eric Brown
    Dec 11 '18 at 0:04










  • $begingroup$
    Hi Eric. No, the inverse of $int_3^xsqrt{1+t^3},dt$ is not $sqrt[3]{x^2-1}$ .
    $endgroup$
    – Mark Viola
    Dec 11 '18 at 0:11














4












4








4





$begingroup$

HINTS:



From the Fundamental Theorem of Calculus, we have



$$f'(x)=sqrt{1+x^3}$$



Moreover, note that



$$f(3)=0implies f^{-1}(0)=3$$



Finally, the theorem from your text book reveals that



$$frac{df^{-1}(x)}{dx}=frac1{sqrt{1+(f^{-1}(x))^3}}$$






share|cite|improve this answer









$endgroup$



HINTS:



From the Fundamental Theorem of Calculus, we have



$$f'(x)=sqrt{1+x^3}$$



Moreover, note that



$$f(3)=0implies f^{-1}(0)=3$$



Finally, the theorem from your text book reveals that



$$frac{df^{-1}(x)}{dx}=frac1{sqrt{1+(f^{-1}(x))^3}}$$







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Dec 10 '18 at 23:53









Mark ViolaMark Viola

131k1275171




131k1275171












  • $begingroup$
    Is my inverse function correct though?
    $endgroup$
    – Eric Brown
    Dec 11 '18 at 0:04










  • $begingroup$
    Hi Eric. No, the inverse of $int_3^xsqrt{1+t^3},dt$ is not $sqrt[3]{x^2-1}$ .
    $endgroup$
    – Mark Viola
    Dec 11 '18 at 0:11


















  • $begingroup$
    Is my inverse function correct though?
    $endgroup$
    – Eric Brown
    Dec 11 '18 at 0:04










  • $begingroup$
    Hi Eric. No, the inverse of $int_3^xsqrt{1+t^3},dt$ is not $sqrt[3]{x^2-1}$ .
    $endgroup$
    – Mark Viola
    Dec 11 '18 at 0:11
















$begingroup$
Is my inverse function correct though?
$endgroup$
– Eric Brown
Dec 11 '18 at 0:04




$begingroup$
Is my inverse function correct though?
$endgroup$
– Eric Brown
Dec 11 '18 at 0:04












$begingroup$
Hi Eric. No, the inverse of $int_3^xsqrt{1+t^3},dt$ is not $sqrt[3]{x^2-1}$ .
$endgroup$
– Mark Viola
Dec 11 '18 at 0:11




$begingroup$
Hi Eric. No, the inverse of $int_3^xsqrt{1+t^3},dt$ is not $sqrt[3]{x^2-1}$ .
$endgroup$
– Mark Viola
Dec 11 '18 at 0:11


















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3034655%2fif-fx-int-3x-sqrt1t3-dt-find-f-10%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Wiesbaden

Marschland

Dieringhausen